The present invention relates to a method for the manufacture of at least one nap fabric tape, provided with a base fabric and with nap elements, by a shuttle-less powered strip loom.
Nap fabric tapes are employed particularly for tape fasteners with two tapes, which each, on one tape side, display coupling means arranged areally. The nap piles forming the coupling means can then perhaps be loop-shaped in the case of one tape and hook-shaped or mushroom-shaped in the case of the other tape.
In a known method for the manufacture of nap fabrics by needle looms, a first shed is formed by basic warp threads and a second by pile warp threads. The weft thread is then introduced each time into the first shed and tied. Each time when nap loops are to be formed, a substantially rigid rod, which in the language of the art is designated as a needle or rod, is introduced in weft direction into the second shed and subsequently displaced in the direction of the warp up to the reed abutment location. The rod then remains in this position at least up to the introduction of the next weft and is thereafter again withdrawn laterally and finally moved back along the warp threads into the initial position. The rod must thus execute a movement with several changes of direction. Due to the acceleration forces arising in the course of this relatively complicated movement, the maximum possible weaving speed is limited to a relatively low value in this prior known method.
A known machine for the performance of this method has two rails displaceable parallel to the weft threads. A rectilinear guide, extending parallel to the warp threads, is fastened to each of these rails. Displaceably guided in each rectilinear guide is a rod, the forward end of which is angled and forms a needle extending parallel to the weft threads. A drive device is further present to push the two rails to and fro separately in their longitudinal direction, i.e. parallel to the weft threads. The machine furthermore includes a drive device with a pusher displaceable parallel to the warp threads. This is so arranged that it can engage the two displaceable rods and push these away against the transport direction of the fabric.
It is now to be assumed that one of the two needles is woven into the fabric and the other is disposed outside the fabric. The latter needle is now first pushed parallel to the warp threads in front of the shed by means of the pusher and then pushed into the shed by displacement of the rails, on which its guide is fastened. Subsequently, the newly pushed-in needle is transported to the reed abutment location by the reed together with the newly introduced weft thread. The pile warp threads running around the needle then form loops. During the next weft insertion, the needle already previously introduced into the fabric is again withdrawn from the fabric by displacement of the respective rail and can then be pushed in front of the shed by means of the pusher. In this manner, the two needles can be pushed alternately into a shed, be transported by the reed to the reed abutment location and then again be withdrawn from the fabric and pushed in front of a new shed. As described, these movements are generated by pushing the rails to and fro and by pushing the needles by means of the pusher. Each needle is thus moved by two different drive members, namely the rail and the pusher. The prior known method and the machine for the performance thereof are therefore relatively complicated and make possible only relatively low weaving speeds as already explained. The latter is the case especially also for the reason that the pusher is not permanently connected with the needles and produces an impact each time it pushes a needle away.
A further method and a further machine for the performance thereof are known from the book "Webmaschinen", which was written under the editorship of H. Hahn and published in 1966 by VEB Fachbuchverlag Leipzig. The machine described in this book includes several rods, which serve for the formation of nap loops and which are designated as rods, however likewise these are essentially rigid rods. Each rod is provided at its rearward end with a platelet, which has a four-sided hole and a slot. The machine includes a rod rail, which serves to guide the rods and which, at its end further removed from the fabric, is pivotably connected with the machine frame by means of a spigot perpendicular to the fabric. The rod rail can be pivoted to and fro by means of a rod rail drive device, so that it extends either parallel to the weft threads or somewhat oblique to these. Further present is a rod carriage, which is guided to be displaceable parallel to the weft threads and can be displaced to and fro by means of a rod carriage drive device.
It is now assumed that one of the rods is disposed in the rod rail and that the remaining rods are introduced into the fabric. The rod rail is now pivoted by means of the rod rail drive device in such a manner, into a position oblique to the weft threads, that the forward rod end gets in front of the shed. The rod carriage is now displaced by means of the rod carriage drive device towards the fabric, while it engages in the slot in the platelet at the rearward rod end and pushes the rod into the shed. When the rod has been entirely pushed into the shed, it gets completely out of the rod rail. The latter is thereupon pivoted back into a position parallel to the weft threads. The rod carriage now seizes the rod disposed in the fabric for the longest time and withdraws this from the fabric into the rod rail. With this, the cycle can again begin from the start.
Also in this prior known method, the rod must thus on the one hand be displaced by means of a drive device along its guide, i.e. along the rod rail, and the rod rail must on the other hand be moved by means of another drive device. The rods, when they are introduced into the shed and are further transported by the fabric, must furthermore in this prior known method be completely separated from the two drive devices and must then again be seized by means of the rod carriage. Only relatively low weaving speeds are therefore possible also with this prior known method.